Project Summary This Alzheimer's Disease and its related Dementias (AD/ADRD) ? focused administrative supplement will build on the aims of the NIA funded parent study, Aging Together: Relationship Dynamics Between the Very Old and Their Old Children (R21 AG054668). The goal of this parent study is to explore the nature and consequences of the very old parent-child relationship and to offer insight into person/dyad-specific characteristics that may be associated with greater risk for poor well-being and care-related outcomes in these dyads. Parent study recruitment focuses on very old parents (age 90+) who are cognitively intact, and their ?old? children (age 65+). Preliminary data from this study suggest that the ?old? children in our target dyads, even in cases of a very positive relationship, feel challenged in significant ways due to the prolonged caregiving tasks associated with their parents' exceptional longevity. Yet, many of them also express enjoying notable ?benefits? of their parents' longevity. These include receiving surprising extents of ?downstream? support from their parents, and the extra ?life? time together sometimes allows coming to terms with long-standing relationship difficulties. However, ?old? children caring for very old parents with dementia may have the disadvantage of missing out on these ?benefits of longevity.? Moreover, dementia caregiving is known to be among the most stressful of all caregiving scenarios to begin with. Our central research question thus is how ?old? children caring for very old parents with moderate to severe dementia, compared to those with cognitively intact parents, experience support exchanges and challenges/rewards within the parent-child relationship, and how these experiences are associated with their mental and physical health. To pursue this research question, we will add a ?booster? sample of 100 children (65+) of very old parents (90+) with moderate to severe dementia. We will conduct an in-depth, semi-structured interview with them that includes both open-ended and standardized self-report assessments of mental and physical health, parent-child relationship quality, support exchanges, and challenges/rewards experienced in this relationship. Our research question will be addressed with the following specific aims: 1) To compare support exchanges and perceived challenges/rewards in very old parent-old child dyads, as reported by ?old? children of parents with moderate to severe dementia versus children with cognitively intact parents. 2) To compare how support exchanges and perceived challenges/rewards are associated with the mental and physical health of ?old? children with parents who have moderate to severe dementia versus those with cognitively intact parents (accounting for parent functional disability and child caregiving burden). Analysis of mixed-method data will involve qualitative (thematic coding) and quantitative (multivariate; multi- group analyses) methodologies. Supplement study results will have a significant impact because they will allow us to capture a fuller range of experiences and realities that ?old? children of very old parents are likely to face.